MASON CAPITAL MANAGEMENT LLC
•CIK: 1218735•Filing: Q4 2025
MASON CAPITAL MANAGEMENT LLC manages $562M across a concentrated portfolio of nine positions. The fund exhibits a significant overweighting in ATS, representing $428.6M of its total assets. Further notable allocations include B7S at $38.7M and SOLS at $30.8M, indicating a focused, high-conviction investment approach. This structure suggests a deep commitment to a select group of large-cap holdings.
Total AUM
$561.6M
QoQ Performance
+14.3%
Positions
9
Top 10 Concentration
100.0%
Latest Filing
Q4 2025
Top Holdings Allocation
ATS
B7S
SOLS
ATS76.3%
B7S6.9%
SOLS5.5%
CCO3.9%
JBS3.4%
BORR1.6%
RC1.5%
MLAB1.0%
📈 Biggest Buys
📉 Biggest Sells
No reductions this quarter
Sector Breakdown
Other100.0%
🚪 Exited Positionssold since Q3 2025
Changes from Q3 2025
NEW4 new positions
↑1 increased
Historical Filings
Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023